Welcome to Health Reform Watch, Sarah Kliff’s regular look at how the Affordable Care Act is changing the American health-care system — and being changed by it. You can reach Sarah with questions, comments and suggestions here. Check back every Monday, Wednesday and Friday afternoon for the latest edition, and read previous columns here.

"Medicare workers in Washington are learning that door-to-door selling is a rugged job," a writer in this newspaper declared 47 years ago.

It was March 3, 1966, after a Washington Post reporter had spent the day trailing Medicare workers who tried to sign seniors up for new program. Some didn't answer the door. Others slammed doors in their faces. One man reportedly stuck his nose out the door to say: "I'm not 65. I'm 57 — just today."

"Sometimes they peek through the windows when they see me coming and they won't answer the door," Medicare worker Jim Anderson told The Post. "They must think I'm selling books or something."

Medicare is, these days, an incredibly popular program. Americans overwhelmingly oppose cutting it. No politician would consider repealing it. Most think providing health insurance to all Americans over 65 is worth the both the trouble and the cost.

This was not always true. Back in 1966, as Medicare was just about to launch, nobody knew whether the new program would provide benefits to millions or fail completely. Sound familiar?

"What will happen then, on that summer day when the federally insured system of paying hospital bills becomes reality?" Nona Brown, a New York Times reporter, wondered in a story published April 23, 1966. "Will there be lines of old folks at hospital doors, with no rooms to put them in, too few doctors and nurses and technicians to care for them?"

Like the Affordable Care Act, the fight over Medicare was contentious. President John F. Kennedy had tried to extend health benefits to the elderly and failed.

The American Medical Association vehemently opposed the law. Two months before President Lyndon B. Johnson signed Medicare into law, the American Medical Association ran ads across the country denouncing the program as "the beginning of socialized medicine."

Johnson signed Medicare into law July 30, 1965. Benefits would become available July 1, 1966. That gave the Johnson administration less than a year to reach 19 million seniors. Medicare was, as the New York Times put it in April 1966, bracing "for M-Day."

The federal government launched "Project Medicare Alert," a program that hired 5,000 workers to enroll seniors in Medicare. The "$2 million crash effort," as described by The Post, was meant to "inform isolated elderly Americans of the availability of Medicare benefits." Workers, hired for a 20-week stint, were paid $1.25 per hour.

There were still concerns about whether the enrollment efforts would actually work. The seniors who needed the program the most, Washington Post columnist William Raspberry wrote, tended to be the hardest to reach. The program came with a $3 monthly premium, and Raspberry worried that "those who will have trouble coming up with the $3 a month are precisely those who can least afford not to enroll."

On the whole, however, the enrollment effort worked. Of the 19 million seniors eligible for Medicare, 93 percent enrolled by the summer of 1966. Social Security Administration Commissioner Robert Ball "enlisted the U. S. Forest Service to send Forest Rangers out into the woods in search of elderly hermits whom he might be able to enroll." And, much to Wonkblog's liking, he held news conferences with charts that showed Medicare's enrollment levels.

Less than a month before Medicare was set to launch, though, one hurdle seemed insurmountable. A front page Washington Post story reported on Johnson making "an 11th-hour appeal for hospitals to end discrimination, but he failed to prevent Medicare's start from being marred by segregation."

Mobile, Ala., apparently had the worst showing on this front: Just 30 of the city's 3,986 hospital beds were certified for Medicare. "The holdout hospitals," Eve Edstrom wrote, "are expected to fall in line once community pressure builds up against denying Medicare benefits to Whites as well as Negroes."

M-Day arrived and ... it was a bit of a dud. "At 12:01 a.m. yesterday," Dan Morgan and Martin Weil wrote on July 2, 1966, "Uncle Sam began paying the hospital bills of close to 1,000 patients over 65 in area hospitals."

Medicare's very first patient, incidentally, was Mary Augustus, 68, of Hartford, Conn. Her hospital received a check for $331.71 for a surgery performed July 1.

The long lines that some had worried about? They never materialized. "At the end of its third week," the New York Times reported July 25, 1966, "the Medicare program was reported going smoothly, with difficulties in some areas of the South still the only major problem."

Even the issues of segregation, which seemed to be a significant threat in early July, had largely been resolved by the end of the month. "By July 21, 1966, fewer than 0.5 percent of hospitals were not certified for Medicare eligibility," Jill Quadango wrote in her history of the program.

Meanwhile, legislators quickly began looking for ways to expand the Medicare program and make it even larger. In January 1966, a young congressman from Michigan proposed a bill that would extend Medicare to cover drugs.

Such a program proposed by John Dingell, now the longest-serving member of the House of Representatives, would not become law until nearly four decades later, when Congress created the Medicare Part D program.

KLIFF NOTES: Top health policy reads from around the Web.

America's most expensive hospital is ... in New Jersey? "Based on the bills it submits to Medicare, the Bayonne Medical Center charged the highest amounts in the country for nearly one-quarter of the most common hospital treatments, according to a New York Times analysis of 2011 data, the most recent available. No other hospital was at the top of the price list more often." Julie Creswell, Barry Meier and Jo Craven McGinty in the New York Times.

Arizona is moving forward with the Medicaid expansion. "The Arizona Senate on Thursday approved expanding the state’s Medicaid program, capping a rancorous debate that had split the Republican Party and had been building since January, when Gov. Jan Brewer issued a surprise call to increase Arizona’s health-care program for the poor." Mary Jo Pitzl and Mary K. Reinhart in the Arizona Republic.

Obamacare appears to be driving down premiums in Oregon. "On Thursday, a comparison of proposed 2014 health premiums became public online, causing two insurers to request do-overs to lower their rates even before the state determines whether they're justified. The unusual development was sparked by a comparison that used to be impossible because plan benefits varied so widely. But under the federal reforms that take effect Jan. 1, health insurance is mandated and every insurer must offer certain standard plans." Nick Budnick in the Oregonian.